That's actually a bit of a trick question, because there's no one structural paradigm that wins out over the others. When it comes to screenwriting, rules and rigidity don't really translate well -- I suppose not even when it comes to structure. However, unless you're working on an avant-garde or experimental piece of cinema, having a clear structure is ideal in order to help your audience understand what's going on in your story.
And if spending another day with your nose inside a screenwriting book bums you out, take a look at this fantastic video by Darius Britt, who is quickly becoming my go-to guy when it comes to screenwriting advice. In it, he breaks down the three-act structure in its entirety, while sharing some truly enlightening tips on where to start, what to look for, and how to fix common issues.
Now, if you're staunchly against the three-act structure, I totally get it. (Though, I think this is a good starting place.) Personally, I'm agnostic when it comes to screenwriting theories; I've written scripts using a bunch of different methods, like the Hero's Journey, 3/5/7-structure, Field's plot points, even saying screw it and making stuff up as I went along. (I call that the "I don't know -- feels right" paradigm.)
However, since all of these theories helped me at some point or another, I like to think of them not as competing theories, but as -- Power Rangers. On their own, that can definitely kick some major Putty Patrol ass, but if you want to defeat Lord Zedd and Rita Repulsa, you've gotta morph, baby, and join forces to become the Megazord of Screenwriting.
There's really no wrong way to write a screenplay, because at the end of the day, if this theory or that theory gets you to the point where you've completed something, then that's all that really matters. Don't let dramatic-structure fanboyism distract you from the most important thing: putting words on the page.
Now -- it's morphin' time!